My comment were intended as a direct reply to phpnode's code, 'ignoring' the rest of the thread.

How do you mean when you state that for(of) is incorrect?

Perhaps this 'example' clears something up?

  « for (value in {a:1,b:2,c:3,d:4,e:5}) console.log(value)
  » undefined
    "a"
    "b"
    "c"
    "d"
    "e"
  « for (value of {a:1,b:2,c:3,d:4,e:5}) console.log(value)
  × TypeError: ({a:1, b:2, c:3, d:4, e:5})['@@iterator'] is not a function